727 no reverse, forward in neutral after rebuild

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slidey06

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Howdy!
I have a 727 that was just rebuilt and put in my 71 duster, put in a cope reverse manual valve body and their billet reverse servo. The car even after the rebuild has no reverse gear and goes forward in neutral, I dropped the pan and adjusted the band, adjusted the shift linkage well, still no luck.

Before the rebuild a tf3 kit was done, I’m wondering if the governor and forward clutch plugs they have you put in that are still in the trans case would cause this issue or what the recommendation is.

Thanks!

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You have a problem in the forward clutch pack. As in, there is a mechanical issue locking the clutch pack all the time. Does it seem to labor/want to move in Park also?
 
thanks for the reply!
No, In park it doesn’t go anywhere when I get on the gas and the wheels are locked.

I should also clarify, this is the same issue I had before i took it to the shop to be rebuilt
 
When you say no rev does the engine rev like neutral or bind?
moparlvr166 said:
When you say no rev does the engine rev like neutral or bind?
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it acts like neutral with the car on in reverse.
If I shift to neutral with the car off the car will move freely however
 
I'll post this once again. Because I care and you all should know,

The car below was My GSS I sold to a friend. He took it to a shop to have a shift kit installed 3 days later. He left his 17 year old son who was leaving for the air force the next day take the car out that night. He was racing a Charger. When he shifted from second to drive the trans locked up. Killing the boy and paralyzing the passenger. Don't let wana-be trans builders take your life in their hands.

The Father bought this challenger off of me and installed the trans from the Demon. Same thing happened entering a highway from an entrance ramp. That is how we knew what happened to his son.

DON"T TAKE THE CHANCE HAVE A PROFESSIONAL DO THE TRANS

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Take it back to Redline and have them fix it if it is the same issue.

The hardest part about rebuilding these is pulling them out of the car. I learned to do my own.
 
Just my opinion, but I wouldn't take anything back to someone that screwed it up in the first place. If they can't do it right for money, they won't do it right for free.
 
I know its a year later but did you ever figure out what the problem was?

This exact thing is happening to mine. 727 bb, rmvb from turbo action. For a long time wont go into neutral when running unless been driving for a while. If you try when not warm enough it makes grinding/buzzing gear noise (real faint but car is loud). Reverse used to work fince once car warm but now no reverse cold or warm. Forward 1-3 engage but havent driven down road so dont know if working fine while driving. Car will go forward with a little gas if you put the shifter between park and reverse...reverse wheels feel locked. Park sometimes wants to initially jump forward a bit then locks into place. Had pan off and fluid looked good with normal limited amount of very fine metal residue in it....low/rev servo spring etc all in place and adjusted to 2 turns out. Didn't check other band. I also didnt pull the servo out so maybe it has a crack or something? I haven't done any air testing or pressure tests at this point. It started doing this after I had up in air (sometimes front end only) replacing all brake components and front shocks.
 
mmbroker68 said:
I know its a year later but did you ever figure out what the problem was?

This exact thing is happening to mine. 727 bb, rmvb from turbo action. For a long time wont go into neutral when running unless been driving for a while. If you try when not warm enough it makes grinding/buzzing gear noise (real faint but car is loud). Reverse used to work fince once car warm but now no reverse cold or warm. Forward 1-3 engage but havent driven down road so dont know if working fine while driving. Car will go forward with a little gas if you put the shifter between park and reverse...reverse wheels feel locked. Park sometimes wants to initially jump forward a bit then locks into place. Had pan off and fluid looked good with normal limited amount of very fine metal residue in it....low/rev servo spring etc all in place and adjusted to 2 turns out. Didn't check other band. I also didnt pull the servo out so maybe it has a crack or something? I haven't done any air testing or pressure tests at this point. It started doing this after I had up in air (sometimes front end only) replacing all brake components and front shocks.
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My bet is your bellvue spring broke in the rear drum and the forward gear clutches are mechanically applied with no return pressure from the bellvue spring. This is why the car wants to move forward in every gear, including park and neutral. In reverse, the low/reverse servo is applied, coupled with the front clutch. So when the front clutch, rear clutch, and low/reverse servo are all applied at the same time, you have a trans brake application. Hence why in reverse it won’t move. The transmission will need removed and disassembled to fix that issue. I would suggest a billet aluminum forward drum piston (.875” tall if stock drum and hub), metal spacer ring, and late model bellvue spring. That’s the fix. It’s also possible the bellvue spring didn’t break and the piston had so much play between the piston and bellvue spring, that once the piston applied, it could have popped out of the bore. Either way, the taller billet piston, metal spacer ring, and late model bellvue spring are the fix. Looking at $150ish total for those few components.
 
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71Demon528 said:
My bet is your bellvue spring broke in the rear drum and the forward gear clutches are mechanically applied with no return pressure from the bellvue spring. This is why the car wants to move forward in every gear, including park and neutral. In reverse, the low/reverse servo is applied, coupled with the front clutch. So when the front clutch, rear clutch, and low/reverse servo are all applied at the same time, you have a trans brake application. Hence why in reverse it won’t move. The transmission will need removed and disassembled to fix that issue. I would suggest a billet aluminum forward drum piston (.875” tall if stock drum and hub), metal spacer ring, and late model bellvue spring. That’s the fix. It’s also possible the bellvue spring didn’t break and the piston had so much play between the piston and bellvue spring, that once the piston applied, it could have popped out of the bore. Either way, the taller billet piston, metal spacer ring, and late model bellvue spring are the fix. Looking at $150ish total for those few components.
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Thanks for the info. It has a no low band apply valve body. Should I keep that and go billet steel front drum and piston, bolt in sprag, and billet low rever servo kit while I'm messing with it? I know change vb to lba would add another layer of safety but trying to find happy medium of safety and cost on a car that is only really street driven right now. Thanks again
 
mmbroker68 said:
Thanks for the info. It has a no low band apply valve body. Should I keep that and go billet steel front drum and piston, bolt in sprag, and billet low rever servo kit while I'm messing with it? I know change vb to lba would add another layer of safety but trying to find happy medium of safety and cost on a car that is only really street driven right now. Thanks again
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I would certainly recommend the LBA valve body for your exact reason stated. Especially on the street, the sprag can be beaten up badly when at stop lights and starting out in first gear and burning tire. If you have a higher power street car that has no issue cutting the tires loose on the street, your at a lower risk than the guy who barely has enough power to turn the tires on dry pavement running a non LBA valve body. Yes highly recommend the LBA valve body. But if you only have money for the bolt in sprag, and billet front drum, and billet solid l/r piston, you are still making the transmission much much safer. The good thing with the valve body, if you have to hold off on buying one because a lack of funds, you can always buy one later and swap it out while the transmission is in the car.

I am currently building a 727 for a street car that is getting an automatic shift valve body.
The automatic shift valve body does not apply the low/reverse band when in drive, but when put in manual low it does apply the band. That is as safe as I can make it given the valve body he is going to be using. He is getting the bolt in ultimate sprag, billet front drum, billet low reverse piston, and some other good upgrades.
 
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dumb question- assuming this is bellville spring/stuck forward clutches, is it ok to drive this thing? Probably 10 miles +/- to friends shop with lift.
 
mmbroker68 said:
dumb question- assuming this is bellville spring/stuck forward clutches, is it ok to drive this thing? Probably 10 miles +/- to friends shop with lift.
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If that’s your only way there, gotta do what you gotta do. I wouldn’t recommend it because I don’t wanna see any more metal go through the trans than already has with the broken spring (which I believe that is your issue). But think of it this way, if that bellville spring broke after you first put the car in drive before a trip, you had no clue there was an issue with it for the duration of the trip until you tried to back up. But after you get it to the shop by whichever means, please update with what is found.
 
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